Yep, that's a good list. However, there are alternatives to those first two steps. It can take quite a bit of work to set up your own CMS, and personally, I prefer to leave that to people who specialize in it. A nice alternative is to use a 3rd party service that hosts the cart and handles security. You can style it to look like the main site so that users don't even know they're on another site when making their purchases. There are many examples of this, such as FoxyCart, eJunkie, Fastpring, Plone, BigCartel etc. Worth checking out if you don't want all the responsibility of setting up a CMS.

Another option is to have a fully hosted site, using something like Shopify or Goodsie.

merchant account is something provided by the merchant processor, correct?I mean when I'm getting a merchant account I'm essentially doing so from a merchant processor?I guess the reverse distinction could be that a merchant processor can ALSO offer additional services, such as gateway that otherwise I would have to get separately on my own if a merchant account is the ONLY thing I'm acquiring from a given merchant processor?

A merchant account—at least where I come from—means a special bank account with a bank. It's really a bank account where all the funds are deposited after the user has entered their details into a shopping cart, which have then been processed by a payment gateway.

Cart > Gateway > merchant account

That's the typical flow. A service like PayPal incorporates all three, and it's not the only one. The problem with these three levels is that each usually has its own fees. So any service that incorporates more than one step is attractive. I'm a fan of Fastspring, as they provide a cart, collect the money, and deposit it in your regular bank account (meaning you don't need a special merchant account). I haven't yet found another cart that does that.

Nowadays you can't forget about social media integration for your e-commerce and mobile readiness. This is crucial, as shoppers have an access to the Internet through their mobile devices almost everywhere and also they are active on social networks. Don't forget to be SEO friendly,as well!

I agree with the previous advice it might be best to look for ready solutions. Handling a webshop on your own, all technical stuff included, is rather time consuming. You could better use this time to focus on selling your products.

Looks interesting, but what's it for? After watching the videos and reading about it, I still don't get what it does. I know that sounds stupid, but it really doesn't say clearly (from my point of view) what I'd use it for.

2. Shopping Cart/PlatformYou can think about hosted or SaaS e-commerce platform. If you're new to e-commerce and have little experience then go for SaaS platform.What makes an e-commerce platform good?

Choose the right payment processor according to your ideal user base and demographic. For example, SagePay is very popular in UK.If you're using Paypal/Google Checkout or similar services, there is no need to open a merchant account at your Bank.

4. SSL CertificatesIf you're using a hosted platform, it's very important. But in case of SaaS platforms, they have already SSL installed.

Checkout Magento Go. It's easy and cheap to start. Once you're generating sales, you can extend Magento Go a bit. In fact the new plugin architecture of Magento will soon have all modules cross compatible among the Go hosted service, Community and Enterprise versions. I think it's a good idea for anyone getting started to use some type of SaaS platform like this. The PA-DSS requirements of July 2010 state that anyone accepting credit cards has to do so through approved applications. This forces people with hosted solutions to used a tokenized payment solution like paypal express or use a bridge like the Magento Payment Bridge or X-Payments from Qualiteam. Changes are you're not going to get busted for not being PA-DSS compliant but still, it's the law. So for getting started, I'd use a SaaS platform like Magento Go.

Just be careful on the solution you use as they may only you to use one or two merchant account providers. I know that Yahoo stores had this issue.One of the key things to be aware of is that not all merchant service providers are the same. Most will have hidden fees and attempt to lock you into a 3 yr contract. Be very aware and do not pay any set up fees as many will try to collect this from you. One company that offers no set up fees or contracts is http://www.prestigemerchantservices.com. SEO is also important if you want to help your site be found and there is a lot of info on the net on how to build a friendly seo website.

You can't have just things to make your e-site work you need it to work well and comfortable for customer. Social media integration, video plagins, extensions for previewing products, to search between them and so on and so forth.